A cotton field in Appling County planted to a heavy cover-crop of rye was fumigated

with Telone II, 4 gal/A, weeks prior to planting. A good stand was established

despite the heavy residue. Fumigation process was difficult because cover crop had

not been “killed”.

Management of Southern Root-Knot Nematode

in Appling County, Georgia

Special Thanks to: Jeff

Deen (right), Greg Black,

Lamar Turner, Satilla Cotton

Gin, Dow AgroSciences, and

Phytogen Cotton Seed.

RESULTS and DISCUSSION (continued)

4. Use of PHY 367 did not result in a decrease of late-season root

galling nor did it result in decline of late-season nematode

populations as compared to PHY 375. PHY 367 out-yielded PHY

375 by 191 lb/A lint.

5. Use of Telone II resulted in numeric increase in yield and gin turn-

out and numeric decline in late-season root damage. Telone II was

the most important production practice in this study to be of benefit

to the grower.

6. Efficacy of AVICTA Complete Cotton to manage nematodes in this

study was tied to the area of the field where evaluated. Where

nematode populations were moderate, the treatment appeared

appropriate.

INTRODUCTION

Appling County lies in the Coastal Plain of southeastern

Georgia. Cotton is an important crop for growers in this county

and management of plant-parasitic nematodes is especially

important as soils in the county are typically very sandy.

Meloidogyne incognita, the southern root-knot nematode, is the

most important nematode affecting cotton in this region.

Growers have historically used aldicarb, Temik 15G, to manage

both thrips and nematodes; however the loss of Temik 15G

early in 2011 necessitated additional field trials to determine

refined opportunities for control of nematodes in Appling County.

The objective of this study was to compare the performance of a

cotton variety with known partial-resistance to the root-knot

nematode (PHY 367B2RF) treated with AVICTA Complete

Cotton to a popular variety without resistance (PHY 375B2RF),

also treated with AVICTA Complete Cotton. Additionally plots

planted to each variety as above and fumigated with Telone II (4

gal/A), were compared to non-fumigated plots. It was hoped that

the results from this study would give growers in eastern

Georgia better idea strategies to integrate nematode resistance

and nematicides into their cotton production practices.

RESULTS and DISCUSSION

1. The field trial at the Jeff Deen farm is pictured in photos above just

prior to harvest. Plots fumigated with Telone II are obvious; however it is

not possible to differentiate plots planted to PHY 367B2RF versus PHY

375B2RF.

2. From nematode samples collected after harvest (Figure 1) it is clear

that the populations of root-knot nematodes in the field far exceed the

economic threshold established for Georgia (100 juveniles/100cc soil).

Despite use of a resistant variety (PHY 367B2RF), high counts were

found in all treatments.

3. Plots originally to be treated with Vydate CLV following emergence

were used as a second set of AVICTA Complete Cotton treatments. This

proved fortuitous as areas planted were more affected by nematodes

than the first set.

ABSTRACT

Management of the plant-parasitic nematodes is of critical

importance throughout Georgia and annually costs producers

more than $100 million. The southern root-knot nematode

(Meloidogyne incognita) is especially important in Appling County

where sandy soils and long-term cotton production allow for

damaging populations of this organism to develop quickly. The

objective of this study was to determine appropriate management

strategies for management of M. incognita with the use of a

partially resistant variety (PHY 367B2RF), a seed treatment

nematicide (AVICTA Complete Cotton) and Telone II. The

population of M. incognita in the field used in this study was as

much as 6X the economic threshold level for the southern root-

knot nematode in Georgia. Little difference was noted between

damage to the PHY 367 versus PHY 375. Yield for resistant PHY

367 treated with AVICTA was 191 lb/A greater than where PHY

375 was planted. Fumigation with Telone II in conjunction with

either variety resulted in a numeric reduction in root-damage and

an increase in yield (413 lb/A).

D.S. Curry1and R.C.Kemerait2

1University of Georgia Coop. Ext., Baxley, GA 315191 and 2Dept. of Plant Pathology, University of Georgia, Tifton, GA,

31793.

Data reported in Figures 3 and 4 are based upon combined harvest of all plots of a given

treatment. Plots for the treatment PHY 367 + AVICTA + Telone II were not harvested due

to error. Seed-cotton yields for plots treated with Telone II were more than 300 lb/A

greater than were yields in plots that were not fumigated. However, based upon reported

gin turn-out, reported lint differences are much greater than anticipated. ALSO: Data for

the AVICTA-ONLY treatments does not include the second set of plots where damage

from nematodes was most severe.

MATERIALS and METHODS

1. A replicated field trial was established on the Jeff Deen farm in Appling

County, Georgia in 2011. This field has a history of losses to M. incognita.

2. The experimental design was a factorial randomized complete block with

3 replications. Treatments included combinations of PHY 367B2RF and

PHY375B2RF (seed treated with AVICTA Complete Cotton) with and

without Telone II (1,3-dichloropropene, 4 gal/A). Fumigation with occurred

weeks prior to planting. The cotton crop was planted on 7 Jun and

harvested on 15 Nov.

3. Vydate CLV, planned as a third treatment to compliment use of AVICTA

Complete Cotton, was not applied. Thus, there were two sets of plots

treated with AVICTA but not Vydate. Yield was not determined for the

second set of these pots.

4. Data collected included soil sampling to determine nematode

populations, end-of-season root-damage ratings, and yield (non-

replicated).

1048

0

200

400

600

800

1,000

1,200

1,400

1,600

PHY 375 + Telone +Avicta

PHY 367 + Avicta PHY 375 + Avicta

1,501

1,279

1,088

Yield/lbs Per acre

Figure 4. Lint Yield based upon gin turnouts reported by Satilla Cotton Gin

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

PHY 375 + Telone + Avicta PHY 367 + Avicta PHY 375 + Avicta

41%

36%

31%

% Lint

Figure 3. Gin Turn-out as determined by the Satilla Cotton Gin

A root system damaged by southern root-knot

nematodes (above, at right). In picture at right,

collecting soil samples after harvest to determine

end-of-season levels of plant parasitic nematodes.

0

10

20

30

40

Figure 2. Galls per gram of root at harvest

PHY367+AVICTA PHY375 + AVICTA

PHY367+AVICTA + Telone PHY375 + AVICTA+ Telone

PHY367 +AVICTA PHY375+AVICTA

B B B B

A A

0

200

400

600

800

Figure 1. M. incognita, juveniles/100cc soil at harvest

PHY367+AVICTA PHY375 + AVICTA

PHY367+AVICTA + Telone PHY375 + AVICTA+ Telone

PHY367 +AVICTA PHY375+AVICTA

NS SPECIAL NOTE: For Figures 1 and 2 two

sets of data are presented

for PHY 375 + AVICTA

and PHY 367 + AVICTA.

Originally the second set

was to be over-treated

with VYDATE CLV. As

this did not happen, the

plots were simply

duplicates of other

treatments. The data are

presented separately here

as results from this study

clearly document that

efficacy of seed-treatment

nematicides is closely tied

to the magnitude of

populations of parasitic

nematodes in a field.

Coincidentally, the second

set of seed treatments

was placed in severely

infected areas of the field.